Radio tuning apparatus



Sept. 2, 1941. H. z. BENTON ETAL 2,254,789 l RADIO TUNING APPARATUS Filed NOV- 15, 1959 2 ShGStS-Sheet l @s Wi 47 l 49 l J4 0261927 ffl j l 43 I l 4] L 'l :H1 I

Sept 2, 1941- H. z. BENTON E- r AL 2,254,789

RADIO `TUNINGr APPARATUS Filed Nov. 13, 19259 2 Sheets-Sheet 2 INVENT R5.

.Ha/0&7J ZE 72,

ATTORNEYS.

Psrenredsepr. 2, 1941 1 a' Chicago, Ill., assignors to Crowe Name Plate & Manufacturing Co., Chicago, Ill., a corporation of Illinois v `Appucsuon November 1s, 1939, sensi No. 304,204

v claims. w1. 14.-)

This invention relates to a new and improved radio tuning apparatus and more particularly to a form of such apparatus adapted for permeability tuning over a wide band of frequencies.

Permeability tuning over a range oi frequenciessuch as the broadcast band, requires a coil and core combination in which the eiective permeability of the core in the combination is variable over a relatively wide range. .This variation can be accomplished by moving either the core or coil in relation to the other, but for mechanical reasons it is customary to move the core. With cores of reasonably high apparent permeability it is possible to accomplish tuning over the desired range by moving a small cylindrical core into and out of a solenoid coil slightly larger in size than the core.

Commercial requirements at present make it necessary to provide a combination of manual tuning over the broadcast range and push button tuning for several stations. vApparatus must be .low in cost and small in size'to fit the smaller,

lower priced units, which comprise the greater part of present commercial production.

It is an objectyof the present invention to provide a new and improved permeability tuner for use with radio apparatus, I

It is a further object to provide a construction in which the tuning may be accomplished by push buttons or by a continuous movable manual tuning device. v

It is also an object to provide a construction of this character in which movable cores and manual tuning means are directly connected to a single movable member which may also be moved by the push button tuning means.

It is another object to provide a construction which is simple and compact and composed of but few parts. v

Other and further objects will appear as the descriptionproceeds.

A preferred embodiment of the invention is shown in the accompanying drawings, in Which--v Figure 1 is a vertical transverse section of the apparatus;

Figure 2 is a plan view with portions broken away to show the construction;

Figure 3 is a front view with portions removed and broken away to show the construction; and

Figure 4 is a horizontal section taken on line 4-4 of Figure 1, with the chassis top broken away to further show the construction.

The unit is shown as mounted on a chassis II, the tuning apparatus being supported in a frame comprising end plates I2 and I3, a front plate I4 and a backv plate I5. `The front plate I4 is provided with a plurality of openings I6 to re- -ceive the push button slides I1. 'I'he reduced rear portions I8 of the slides I1 extend through openings in the rear plate I5. Each slide I1 has a transversely extending section I 9 located in front of and spaced from'the front plate I4, and the front end portion 20 oi each slide extends parallel to the main body of the slide. Each slide I'I carries a half-circular cam member 2l which is pivoted thereto at 22, and which'has contact portions 28 and bar 25.

Each slide Il has a laterally extending lug 26 having a threaded opening therein to receive the clamping screw 21. The outer endof this clamping screw is guided in an opening in the transverse portion I9 of the slide and has a slotted end portion 28 extending parallel to the end portion 20 of the slide. The clamping member 291s tted over the slide lug 26 and has a body portion located between the screw2'l and the body of the slide. It has an upturned end. portion 30 which is engaged by the end of the screw 2l. When the screw 2l is moved inwardly it engages the upy turned end 30 of the clamping member 29'to force it against the cam member 2| and retain it in adjusted position.

The rear reduced portion I8 of the slide has the compression coil spring 3| tted around it, with one end bearing against the inner face oi the rear frame member I5 and its opposite end engaging a shoulder 32 on the slide. The slide is v provided with a stop lug 33 which is held against the'inner face of the front plate I4 by the force of the spring 3 I.

The push buttons 34 are hollow in form and are tted over the'ends of the slides I1, as shown in L Figures 1 and 2. The push button members 34 are provided with internal webs 35 which retain the portions 20 of the slides against the adjacent inner face of the push button member. The push button members 34 are provided with recessed faces to receive cards 36 adapted to bear the designation of the station to which the push button maybe adjusted. Due to the fact that the ypush button extends rearwardly beyond the transverse portion yI 9 of the slide and engages the body. of the slide as well as the portion 20, the connection is such as to prevent wobbling of the push button relative to the slide.

The treadle bar 25 is pivotally supported in the end plates I2 and I3. The axis of rotation of the bar is in the plane in which the pivots 22 of the camsl 2I slide. The treadie bar 25 has an up- .,24 adapted to engage the treadle turned portion 31 to which is secured the operating member 38. The upper end of the member 3B carries the gear sector or arcuate rack 38 which meshes with a small gear 40 secured to shaft 4|. The shaft 4I is rotatably supported in the end plates I2 and i3 and carries the drum dial 42. The opposite end of shaft 4| carries the kn'urled disc 43 by means of which the shaft 4| and associated parts may be rotated. The lower portion of the operating member 33 is formed as 'a downwardly extending arm 44` carrying the transverse bar 45. As shown in Figure 3, a small arm 45 extends downwardly from the opposite end of the treadle bar 25 and carries the other end of the bar 45. The member 4G has no upwardly extending portion or rack portion.

The U-shaped members 41 and 45 extend downwardly from the under face of the chassis and carry the coils 49 and 50 mounted on the cylindrical members 5| and 52. The cores 53 and 54 are slidably mounted in the tubes 5| and 52. As best shown in Figure i, the core 54 is provided with an eye 55 into which is hooked one end of a thrust rod 55, the opposite end 51 of which is arcuate in shape and engages the operating bar 45. The coil spring 58 extends around the rod 56 and has its opposite ends hooked into the eye 55 on the core and around the operating bar 45 so as to prevent any slack between the rod 58 and the core and bar 45. The core 53 is similarly connected to the operating rod 45. f

The device may be operated either by manual rotation of the knurled disc 43 or by any one 'of the push buttons 3i. Rotating the disc 43 serves to rotate the drum'dial 42 and by means oi the gear 40 and gear sector 39 also serves to rotate the treadle bar 25. At the same time the arms 44 and 46 are swung to the right or in the counterclockwise direction, as seen in Figure 1, to slide the cores 53 and 54 into their associated coils. A reverse movementof the disc serves to draw the cores out of the coils. It will be seen that the coil springs 3| on the push button slides serve to keep the contact portions 23 and 24 of the cams 2| out of the path of the treadle bar 25 during such manual operation.

The push button slides may be easily set up for the desired stations. The push button member 34 is drawn off the end of the slide and by means of a screw driver the screw 21 turned to unclamp the cam 2|. The set is then tuned to the desired station by means of the knurled disc 43 and the slide forced inwardly. The contact portions 23 and 24 of the cam engage the treadle bar 25 to bring the cam to the proper position and the cam is then clamped tightly by screwing in the screw 21, after which the slide may be released and its push button 34 again put in place.

The construction is compact and composed of but few parts. The member 38 at one end carries a rack for rotating the drum dial upon push button operation, and this rack serves in reverse manner to transmit movement to the treadle bar from the dial when it is manually rotated by the knurled disc 43. Regardless of the method of moving of the treadle bar 25, the arms 44 and 46 swing the operating bar 45 inwardly and outwardly and move the cores relative to their coils to tune the set. The push bar and spring construction connecting the bar 45 and the cores, prevents any back lash or lost motion at this point and insures that the cores will always be brought to the same point when the treadle bar 25 is given the same angular position. The rack and gear connection between the treadle bar and dial causes the dial to rotate through a substantially greater arc than that through which the treadle bar moves, which permits the considerable spread` of the indicating marks upon the dial, which facilitates tuning the set.

It will be understood that the tubes 5| and 52 supporting coils 49 and 50 may be made of any suitable insulating material and the coils will be wound in accordance with the requirements of the particular circuit used. The coils may be aligned relative to the cores by moving each coil tube in its supporting U-member. It will be understood that the coils may be enclosed in shield cans or shielded in any usual manner, if. desired or required because of the location of other elements of the circuit. i

While certain preferred embodiments have been shown by way of example, the apparatus may be modiiied to meet differing conditions and requirements and such variations are contemplated as come within the spirit and scope of the appended claims.

What is claimed is:

1. Radio tuning apparatus comprising a frame, a treadle bar rotatably supported in the frame, means associated with the treadle bar for selectively rotating it to a desired position, a rotary indicator dial, a gear connected to the dial, a rack meshing with the gear and connected to the treadle bar for rotation with said treadle bar, a tuning device, an arm rigidly connected to the treadle bar and a slack preventing link connected'with said arm for operating the tuning device.

2. Radio tuning apparatus comprising a frame. a treadle bar rotatably supported in the frame, means associated with the treadle bar for selectively rotating it to a desired position, a rotary indicator dial, a gear connected to the dial, a rack meshing with the gear and connected to the treadle bar for rotation with said treadle bar, a tuning coil, a core slidably tted in said coil, an arm rigidly connected to the treadle bar, and means connecting the arm and core for sliding the core relative to the coil upon rotation of the treadle bar.

3. Radio tuning means comprising a frame, a treadle bar pivotally mounted in the frame, a plurality of push button means movably mounted in the frame and carrying members adapted to engage and operate the treadle bar, a rotary in-v dicator dial carried by the frame, a gear connected to the dial, a gear sector carried by the treadle bar and meshing with the dial gear, a tuning device, and means connected to the treadle bar for operating the tuning device.

4. Radio tuning means comprising a frame, a treadlebar pivotally mounted in the frame. a plurality of push button means movably mounted in the frame and carrying members adapted to engage and operate the treadle bar, a rotary indicator dial carried by the frame, a gear connected to the dial, a gear sector carried 'by the inner end of said slide for engagement with said treadle bar, the outer end of said slide being angularly extended, a lug on the side of said slide in line with said angularly extended portion of the slide, a clamp plate engaged over said lug and overlying the edge of said pivotally mounted cam, a'screw projecting through said angularly projecting portion and through said lug into holding engagement with said clamp plate and a. hollow push button removably engaged over said angularly extended outer end portion of the slide.

6. RadioI tuning means, comprising a frame. a treadle bar rotatably supported in said frame. a gear segment carried by said treadle bar, a shaft journalled in said frame, a pinion on Isaid shaft in mesh with said gear segment, .a rotary indicator on said shaft, a tuning knob on said shaft and by which said dial may be adjusted and said gear segment be adjusted to change the setting of the treadle bar, connections extending from i said treadle bar for operating a tuning device and push buttons having adjustable cams for vari ously operating said treadle bar.

'7. Radio tuning means, comprising a frame, a

Atreadle bar pivotally mounted in said frame,

means movably mounted in said frame and carrying members engageable with said treadle bar for rotating the same to different desired positions, a rotary shaft journailed in the frame above said treadle bar, gear connections between said treadle bar and shaft, whereby said shaft may be rotated from or serve to rotate said treadle bar, an indicator dial carriedby said shaft, a tuning knob connected with said shaft, a tuning coil mounted in the frame to the rear of said means for Operating the treadle bar, a ymovable core operating in said coil, an arm carried by the treadle bar and means connecting said arm with said core for shifting said core relative to the coil upon rotary adjustment of said treadle bar.

HAROLD z. BENTON. LLOYD P. MORRIS. 

